Rotor grinder machine



51. ABHAUING.

Sept. 25, 1945.

L ILLMER ROTOR GRINDER MACHINE Filed Nov. 20, 1943 Examine 5Sheets-Sheet 1 Err-1A.

INVE N TOR:

51. ABRADING.

Examine Sept 1945- l L. lLLMER 2,385,445

ROTOR GRINDER MACHINE Filed NOV. 20, 1943 5 Sheets-Shut 2 o INVENTOR"-rrw 4" 0|. l-mrmuuvu. EAZIHIIIIE Sept. 25,1945. 2,385,445

ROTOR GRINDER MACHINE Filed Nov. 20, 1943 5 Sheets-Sheet 3 INVENTOR:

51. ABRADING. Examine p 25, 1945- L. ILLMER 2,385,445

ROTOR GRINDER MACHINE Filed Nov. 20, 1943 5 Sheets-Shea t 4 OI.Abrmullw.

p 1945. L ILLMER 85,

ROTOR GRINDER MACHINE Filed Nov. 20, 1943 5 Sheets-Sheet 5 '1r///////////. WNW

txammei 51. ABRADING.

Patented Sept. 25, 1945 Examin UNITED STATES PATENT OFFICE 19 Claims.

The present invention broadly relates to the art of surface grinding andpolishing equipment, and is more particularly adapted to abrasivelytreat a comparatively wide band of sheet metal, multiple strips or thelike flat stock in successive stages while sheathed about the perimeterof a driven rotor drum as a work piece. My unitary machine is of thedragged work piece type designed to efficiently pregrind and to polishhigh tensile sheet stock such as annealed or tempered steel platewithout requiring any rapidly moving members other than a fast movingwork piece which of itself furnishes the necessary cutting velocity forintensive abrasive action.

It is preferred to work with a single power driven rotor of adequatediametrai size that may be housed between laterally spaced framestandards. Such uprights also constitute racks between which to erect arow of tape supply spools and a corresponding row of driven feed reelsthat positively pull multiple roll tapes through separate cutting zonesat a slow rate of linear advance.

Distinctive grades of tape respectively possessing a coarse and finegrit characteristic, may be carried by certain of said supply spools.The width of each individual tape is purposely kept materially narrowerthan the marginal dimension of the treated plate, the respective cuttingzone ends of like grit being overlappingly staggered to constitute acombined zone length that spans the entire plate width. Sectionalizedpressure applying shoe units may be provided to floatingly mount suchtapes and these units may be collectively backed by header means servingto independently impress such several tapes toward their treated plateunder substantially equalized cutting thrust.

The present mode of treatment is in part based upon the teachings setforth in the Illmer and Pallas Patent No. 2,338,644, issued January 4,1944, in which multiple cutting zones are spacedly distributed to lie inan are about the rotor axis. This earlier embodiment has been improvedupon to lower production costs by the addition of perfected controlfeatures.

In the pri sent instance, my rotor sheath may be prefabricated tofacilitate its rapid application, and vnen installed, may be subjectedto tangential tension by compensating means. In addition, provision ismade for shiftably guided header means that may be power oscillatedabout trunnions to selectively bring different grades of grit intoalternative grinder zones while my rotor remains operative.Interlockingly clutched feed means actively drags appropriate tape gritthrough one such alternative cutting zone. The supply spool rack hasbeen arranged for quick replenishment of spent tape to attain a wellsustained machine output requiring the minimum labor requirement andshutdown period between grinder runs.

The object of my invention is to devise a compact grinder machine of theindicated character adapted as a unit to handle a single kind ofabrasive or multiple abrasives of distinctive grits that may beselectively shifted from inactive into active position for successivelyapplying such several abrasives on a rapid low productive cost basis persquare foot of completed sheet output. Embodied herein are also controlrefinements and improved devices for quickly rough grinding or finishingflat stock while applied to a cylindrical portion of an impelled rotorwhereby to promote servicing and satisfy other operative requirements.

Reference is had to the accompanying five sheets of drawings which areillustrative of a preferred exemplification, and in which:

Fig. 1 is an elevational side view of my assembled grinder machinesubstantially held to scale, and Fig. 1A fragmentally represents amodified detail.

Fig. 2 shows a front end view of said assembly with the rotor depictedcross-sectionally.

Fig. 3 illustrates a sheath compensating device taken along 3--3 of Fig.2, and Fig. 4 is a transverse view thereof.

Fig. 5 presents a face view of a ratchet sprocket taken along 5-5 ofFig. 2, and Fig. 6 is a crosssection thereof.

Fig. 7 exhibits a rear elevational view of my machine assembly, and Fig.8 shows in perspective, a preformed plate of semi-cylindrical shape madeready for sheathing my rotor.

Fig. 9 fragmentally details a trunnion shaft with mated cantilevers ofwhich corresponding ends are bridged by similar header beams, and Fig.10 is taken cross-sectionally along l0l0 of Fig. 9.

Fig. 11 schematically indicates the overlapping edgewise dispositiongiven to my staggered tapes, and Fig. 12 is a side view of a tapebacking shoe.

Figs. 13 and 14 respectively show a cross-sectional and a face view ofmy tape supply spool.

Figs. 15 and 16 correspondingly show similar views for a tape ofltakereel.

Fig. 17 corresponds to Fig. 3 and reveals alternative sheathcompensating means.

Referring more seciflcally to Figs. 1 and 2, such grinder assemblycomprises a driven rotor that may be subdivided into plural sectionslOA, HIB etc. of standardized rim width. These sections may be mountedin tandem upon a common horizontal axle H to build up a prescribedoverall width W (see Fig. 11). Said axle may be carried between thebearings 12 and I3 respectively mounted upon separate pedestals such asH that project forwardly from the erected spaced housing standards 15and IS. The contour of each such hollow frame member may be recessed toprovide for a throat that amply clears the rotorfor servicing. The rearframe edges may be disposed vertically as shown and equipped withailixed top and bottom cross plates I8 and I9 that may be laterallyre-enforced in any suitable manner. A depressed frame step 2|] maylikewise be platen connected to further provide for a rigid unitaryhousing structure.

The rotor axle may be driven from a primary motor (not shown) throughthe main tractor pulley 22 or an equivalent centralized planetary gearreducer. My rotor is preferably held to a diametral size that willimpart a pcripheral velocity of several thousand feet per minute to itsapplied sheath. As detailed in Fig. 1, the rotor rim sections IDA, |Betc. may individually or integrally cast in metal and respectivelyprovided with an endless cored jacket 23 whose cooling fluid maybeentered into one drilled axle end through the slip fixture 24 anddistributed in parallel by the controlled intake piping 25. Theresulting artificially induced cooling is added to the natural rotorradiation into the atmosphere. The circulated fiuid may be carried 011by the outlet piping 26 through the other axle end as shown. Such flowdisposition substantially equalizes the temperature in all sectionswithout tendency to warp the rotor perimeter when operating underintensive rough grinding conditions.

Diametrically opposed perimetric regions of my rotor may be providedwith sunken channel like cross grooves or parallel niches 21 and 28 ofwhich the bottom wall may be kept imperforate to allow of incorporatingthe jacket 23 thereunder (see Fig. 1). In each such niche there may befixedly installed a pair of spaced guides 29 and 30 of which the firstnamed is shown provided with a leading sheath gripping edge 3|. Slidablyinterposed between such guides is a keeper bar or the like compensatingmeans 32 of which the shiftable trailing edge 33 may be reverselybeveled to its opposed anchored guide edge 3| and have said keeperoverlappingly concealed behind the applied sheath 38 in the Fig. 3manner. Said bar may extend through all of the rotor sections and haveits overhanging ends conjointly actuated by a pair of similar leverssuch as 34 afllxed to a common rock shaft 35. Compression. springs 36may energetically urge the bar edge 33 toward its opposed guide edge andtend to automatically close the interposed gap marked G.

Fig. 8 discloses a constituent style of semicylindrical plate stock orthe like curved sheath component with which it is preferred tosegmentally embrace the rotor perimeter. The sheath width W may be keptsufliciently wide to span plural rotor sections but equivalent multiplebands may be substituted in lieu thereof. Where the entire rotor rim isto be overlaid, the curled portion of each such sheath component may beprefabricated by bending roll means from moderately thick sheet stock ofstandardized overall length having the respective ends radially inturnedby power driven die creasing means into a hook-shaped lip 39. Thearcuate span between such complementary lips may be accurately held to apredetermined size that will properly fit between the gripping edges 3|and 33 respectively lying in the opposed rotor niches 21 and 28. Suchpreforming practice readily allows relatively heavy plate stock to beshaped up without unduly delaying active grinder performances. It willbe observed that the effort exerted by the spring 36 is wholly directedtangentially of the cylindrical rim and hence does not require the lipregion of my applied sheath 38 to be progressively creased or otherwisedeformed while being stretched into place.

By means of a motorized socket wrench, the thrust spring 36 may beforcibly compressed through the screw shank 40 see (Fig. 3) and therebyopen the gap G with dispatch. By then hooking a sheath lip 39 onto aleading guide edge 3|, the complementary lip of an applied sheathcomponent may be dropped into place. By now unscrewing said shank torelease its spring 36, the installed component may be maintained underconsiderable tangential tension to snugly fit and thereby minimize theair gap between the applied sheath and its rotor perimeter. This aspectassumes importance in that an interposed thick air gap or othercushioning means would constitute the principal hindrance in conductingheat fiow into the underlying water jacket 23. The gap G is preferablykept reasonably narrow so as to be readily bridged without allowing thespanning tape to saggingly enter therein to an inordinate extent.

The aim is to intensively rough grind an applied sheath without allowingits temperature to rise beyond reasonable limits for immediate handling.Said spring actuated keeper bar assembly constitutes self-compensatingmeans that automatically follow up expansion and substantially maintaintangential tension, after the treated sheath has become hot underprolonged abrasion. Such compensation prevents a material enlargement ofthe initial air gap by sheath slackening or buckling.

As an alternative arrangement, attention is directed to Fig. 17 in whichthe primed numerals correspond to the similar Fig. 3 element. Suchmodified compensation is especially suited for an air cooled rotorsheath 38. A non-jacketed rotor rim 98 may be transversely split toleave a slot 28'. Said rim may be cast of metal or made of heavy platestock such as rolled aluminum having an expansion and a heat conductioncoefilcient superior to the treated sheath 38'. Said slotted rim may beinteriorly re-enforced by a welded bridge strap 99 of like material. Themodified toggle type of keeper bar 32' may by a tongue connection, betiltably mounted in its slot to hingedly swing outwardly into its dottedposition by the aid of a turn buckle I00 that thrusts against a fixedpivot |0|. Such keeper thust is again directed tangentially of the rotorrim without either lip end region of my preshaped sheath 38 having to befurther cimped by such thrust.

One sheath lip may engage the gripping edge 33' of a raised keeper andunder toggle action be tightly drawn into operativ position by ashortening of the turn buckle. The sheath 38' is thereby subjected toinitial tangential tension without need for the springs 36 of Fig. 3.When such installed sheath becomes heated by prolonged abrasive action,it promptly shares a substantial heat portion with its underlying rotorrim and at the same time sets up sufilcient difierential expansion tokeep the sheath taut on its run.

A twin sheath component may likewise be applied to complete the otherhalf of the rotor perimeter. If desired, a single sheath of extendedlength may be substituted for semicylindrical components and bedraggingly applied to run in unison with a portion of the rotor rim,particularly where the treated stock is kept relatively thin as in tinor terne plates. Subsequent to the removal of a heavier finished sheath,such ini tially warped sheet may by stretching or counterrolling berestored to its original flat condition.

The forward portion of my rotor is purposely kept accessible forconvenient sheath manipulation by an attendant standing upon the frontplatform where my divers remote switch controls are preferably located.To facilitate rapid sheath replacement by a slow preparatory turning ofthe rotor, an auxiliary motor-driven gear reduction box 4| may beprovided, for having a slow speed output shaft equipped with a sprocketpinion 42 that chain drives the ratcheted axle sprocket 43 (see Fig. 2).As detailed in Figs, 5 and 6, the latter sprocket may include springretained roller pawls or clutch means 44 through which the rotor may beintermittently turned while applying its sheath thereto. Said pawls aredirected to grip the sprocket 43 when the drive pulley 22 remainsstationary. However after this pulley becomes operative, the rotatingaxle is made to overtake the released rollers and leave the reducer 4|standing idle.

The preferred mode of abrading the exposed sheath face will now bedefined. Fig. 1 illustrates a suitable layout of my multiple tapesupplies which may be stowed upon a series of roll-carrying spools suchas 45 that suflice for a full days run. By dismantling the spool sideflange 46 (see Figs. 13 and 14), a roll of abrasive tape 41 may becentered upon the hub 48 which may be releasably doweled at 49 to thespool shaft 50. As commercially furnished, roll tape is commonlyprovided with a comparatively small standardized bore. Spaced guide rodssuch as 52 may horizontally direct the off-coming tape while held tautby the flange engaging drag clip 53.

As represented in Fig. '7, an erected row of independently demountablespool shafts such as 50A, 50B etc. may respectively be bracketed inarallelism between the housings l5 and I6. Each such shaft preferablycarried a plurality of laterally spaced spools 45 that are staggeredwith respect to the spools carried by a certain other shaft to providefor a small tape lap marked L. The grouped SpoOl disposition is such asto afford an edgewise overlap for my staggered grinder zones of the kinddepicted in Fig. 11 and thereby constitute a combined, virtuallycontinuous cutting zone length that extends across the entire sheathwidth W. One or more of such abrasive zone groups may be spaced in anare about the rotor axis in the manner of the Fig. 1 layout. In order tosuccessively pregrind and finish a common sheath, tapes of differentgrits may be stowed upon next adjacent spool shafts such as 50A and 503.

The frame standards may be further bridged by complementary trunnionshafts 54 and 54'. Aflixed to the respective end regions of each suchtrunnion are aligned cantilevers 55 and 56 of which correspondingextremities may be rigidly spanned by a header beam 51 or 58, saidopposed beams being dihedrally inclined with respect to the rotor axis.The laterally spaced tape distribution associated with the trunnion 54is intended to be staggered relative to the tapes backed by the matedbeam on the other trunnion 54' (see Fig. 7).

As exemplified in Fig, 10, each beam may be provided with one or moretransverse bores or the like apertures such as 59 respectively having atubular slide 60 mounted therein in a registering backing relation tothe corresponding tape that co-operates therewith. A closed end of eachslide may be forked for the reception of a pivotally mounted tapebacking shoe 6|. Such relatively short shoe segment may slightlyoverhang its narrow tape 4'! in the Fig. 12 manner, said shoe throughoutits length preferably being kept inherently rigid in order that itsdeflection under operative loading, may not exceed the resulting chipdepth G presently to be defined.

Mated idler or tape guide rollers 62 and 63 may respectively be carriedalong opposite sides of each header beam with their roller end flangesarranged to accurately retain the several tapes in proper registry withcorresponding backing shoes. Resilient means such as the compressionspring 54 may be installed within each slide 60 to floatingly back theshoe thereof. An abutment plate 65 may arrest such spring thrust whenthe shoes are shifted into a neutral position designated H in Fig. 10.After said shoes are brought into operative position. such stop meansmay also prevent tape from unduly entering the sheath gap G of Fig. 3.

By slightly rocking the trunnion shaft 54, the shoes associated with onesuch header beam may collectively be brought into engagement with therotor sheath. The degree of backing pressure which the engaged springs64 respectively exert upon such interposed tapes, may be regulated bythe tilt given to a loaded beam. Because of its magnitude, the aggregatespring reaction falling upon a fully loaded beam is likely to set upconsiderable deflection.

It is emphasized that such multiple narrow tape components when used incombination with individually stiff backing shoes, maintain asubstantially even pressure intensity across the whole length of acombined cutting zone irrespective of the accompanying beam deflection.To mak any required minor correction, the initial tension of the spring64 may be adjustably set by the screw 66.

Corresponding ends of the trunnion shafts 54 and 54' may respectively beprovided with an extended arm 68 and with a short rocker arm 61 (seeFig. 1). Such reversed arms may be interconnected by the adjustable tierod 69 having stub ends. The socketed rod ends may respectively beprovided with right hand and left hand threads adapted to co-operatewith their stub shanks pivoted to said arms as shown. The upper rod endmay be circumscribed by an aiiixed spur gear 10. A remotely controlledreversible motor H resting upon the step 20, may be geared to adepending slow speed outlet shaft having a pinion 12 that meshes withthe gear 10.

Upon starting said motor to rock both trunnions in unison, coarse gritof from 20 to 30 mesh may initially be shifted into active engagementwith the exposed rotor face. After laying a suitable foundation by suchpregrinding, finer grit may be speedily applied to smoothly finish thesheath without rotor removal. The extremity of the extended arm 68 maybe provided with a graduated indicator [4 to visualize the prevailingExamiv setting of the applied shoe springs 64 for eitherv coarse or finegrit grinding.

It is preferred to so regulate the feed rate of all tapes that theirgrit life may become substantially spent in a single pass through eachcutting zone. The abraded sheet stock then emerges from a practicallyfully loaded grit region of the applied tape which tends to impart avirtually burnished finish to the treated sheath face. For a givenbacking pressure, the resulting rate of grinding is unaffected by gritwear and remains substantially constant as long as slowly fed tape isuniformly supplied.

Should a still brighter polish be sought after applying fine grit, therotor may be further equipped with beam suspended pairs of supplementarybuffer wheels 15 and 16 that may extend across the sheet width W and beshiftably mounted upon a treadle 11 as in Fig. 1A. Such radially pliantbuffers may be retarded relative to the sheath velocity by the crossedelastic belt 18.

It now remains to point out the feed mechanism by which mated tapecomponents may be positively drawn into their respective cutting zonesat a substantially uniform rate of advance. Such feed roller means mayreside in the takeup reel detailed in Figs. 15 and 16. A row of drivenreel spindles such as 79A, 793 etc. may be parallelly mounted between myhousing standards to co-operate with their corresponding spool shafts inthe Fig. 7 manner. Each such spindle may mount spaced multiple reelssuch as 80. The flanged hub 8| thereof is preferably kept materiallylarger in diameter than the supply spool 45 in order that the spentreeled tape shall not build up to an excessive depth. The bottom end ofeach such reeled tape may be aflixed against slip by the clasp toe 82.

All reels on any one such spindle may be keyed to rotate simultaneously.A worm gear 83 may be mounted upon each corresponding end of the severalreel spindles. Vertically installed in radially opposed relation to suchrow of worm gears, are a pair of feed shafts 84 and 85. These parallelshafts may each be equipped with plural worms such as 86 or 8! thatrespectively engage alternate gears as shown in Fig. 1. The upper end ofeach feed shaft may be provided with a jaw clutch 88 of which mated jawsthe respective movable members may be reversely shifted in unison by thecontrol lever 88.

A vertical double reduction gear box 98 provided with a variable speedmotor 8| may, through an interposed slow speed output gear, selectivelydrive either clutched feed shaft 84 or 85 through one of the twin spurgears such as 92. The control lever 88 may be interlocked by the link 94to move in unison with the extended lever 68. One end of such link maybe provided with a spring retained slide block 95 disposed to yieldshould a shifted clutch jaw fail to fall into immediate registry priorto starting the remotely controlled tape feed motor 9|.

Since the several reels are gear driven and positively aflixed to theirrespective tapes, the feed rate of all actively advanced tapes may bekept substantially identical. The slightly accelerated feed rateresulting from accumulation of tape on their re .pective reels, may becompensated by a speed change in the motor 9|. A materially differentrotative rate on part of the feed shafts 84 and 85 may be had by the useof unequally sized clutch drive gears such as 92.

As will appear from the Fig. 1 assembly, the several sets of offtakereels and their corresponding supply spools, are respectively arrangedto provide for non-interfering tape travel paths designated 41A, 413etc. that are individually threaded over guide rollers and led towardtheir associated backing shoes. Upon falling into operative engagement,the jaw clutch 88 of the feed shaft will gear drive both of the reelspindles 19B and 19D in unison. After pregrinding the rotating sheathface with coarse tape, the motor H serves to shift the header beams andthereby bring the fine tape spindles 19A and into service. Finally whenall beams are placed into neutral position, the buffers 15 and 16 may beapplied.

Certain appended claims have been drawn with the following standpoint asa basis: Corresponding engaged header beams marked 58 in Fig. 1 asrespectively mounted upon the mated trunnion shafts 54 and 54 andsupplied with tape of like grit, may in association with their shoecomponents 6|, be considered as constituting primary dual presseragencies, whereas the opposed raised beams marked 51 together with theirreleased shoes, collectively make up companion dual presser agencies. Itwill be obvious that both such primary and companion agencies need notbe combined as described since one such suffices where a dual grittreatment is not required.

The purpose in fully motorizing my more essential controls, is toachieve a saving in labor costs which may otherwise constitute the majoritem in production expense. As a further refinement, provision has beenmade to quickly replenish the fully spent tape supplies. Accordingly, Ipreferably provide for simplified clutch means between each reel spindleand its worm gear 83 as shown. In the present instance, a releasableflange 96 may be keyed to its spindle and be withdrawably doweled at 81to the gear thereof.

Assuming the several supply spools 45 each initially carry a fresh rollof tape and the tape backing shoes to stand in neutral position, thenafter such supply has become substantially exhausted, an appropriatespindle flange 96 may be uncoupled to allow of reversely transferringthe spent tape back to its original spool. After the reels are striptand the respective tape end regions come into adjacency with acorresponding supply spool, such ends may be severed to permit of bodilydismounting any one of the shafts such as 50 and of installing a freshlysupplied substitute shaft. The respective free roll ends of each renewedtape supply may then be stapled to a corresponding severed tape end anddrawn onwardly along a threaded tape path beyond its associated shoe 6|.The recharged machine is thus made ready to continue grinding without anextended shut down period.

In order to basically present the characteristic performance of my dragtype of grinder machine. its underlying behavior may be more preciselyset forth by the following empirical equation deduced from extendedresearch work for floatingly mounted abrasive elements whose grit issubstantially spent in one pass through a cutting zone I P" V" g ab outwhere g=so called mean chip thickness or realizable grit penetration perpass under dry cutting conditions, inches.

P=intensity of applied tape backing pressure, lbs. per sq. in. of gritembedded contact area.

V=linear cutting velocity of a dragged work piece surface, feet per min.

n=fractional exponent lying between A and /3,

with a mean value of about 0.3.

M=abrasive grit for roll tape as measured in terms of its sieve mesh perinch.

TS-mean tensile strength of abraded steel stock, this beingapproximately proportionate to its degree of superficial hardness, lbs.per sq. in.

It will be observed that the single pass out G is inherently limited indepth by the grit mesh M, also that g does not increase directly withthe applied unit jaw pressure P but only with a certain root thereof.The maximum allowable value of P is found to rise with the TS factor butto drop with V, that is to say when working at a fast cutting velocity,the permissible jaw pressure is reduced to obviate tape failure.

Where the diameter of the sheathed rotor such as [A is kept sufficientlylarge, it presents a virtually fiat contact area or grit embeddedcutting zone for which its allowable pressure P may without tapefailure, be held at a materially higher intensity than for a treatedcurvature of much smaller radius.

The cubic inch of abraded metal delivered per minute per inch of tapewidth, may be determined by the product (2 VAg, wherein A represents theeffective cutting zone width as taken in inches. The flat shoe 6| of theinstant machine may work with a tangential width of about onehalf inchwidth which calls for a proportionately fast one pass tape feed in orderto maintain the whole zone extent at maximum cutting capacity. The citeddelivery product also represents a measure of the power driverequirements.

Intensive coarse grit grinding necessitates the imposition of amplepressure intensity which in turn sets up considerable internalfrictional drag or power wastage by heating. As intimated, it istherefore preferred to operate with a relatively fast sheath velocitycombined with a moderate pressure in order to attain high cuttingefliciency, lowered heat losses and a generally superior output for agiven size of grinder machine.

Under dry coarse grit conditions, a cut depth G of about inch may berealized with moderately hard steel. Since this cut is successivelyremoved around the entire sheath length during each revolution, anintrinsically high rate of stock removal may be attained with thepresent equipment. As a result, individual sheets may be completelytreated in a comparatively short time and my associated control devicesserve to correspondingly minimize the grinder attendance costs. As afurther attribute, my compact vertical machine may be kept reasonablylow in first cost. and occupies relatively means together with ashiftably mounted abrasive element possessing a certain gritcharacteristic and which element is operatively interposed between saidbacking means and 2. treated side face of said sheet to establish acutting zone extending crosswise of said sheet, companion presser agencymeans embodied as a constituent of the same machine and operativelyarranged to abrade said face in a manner substantially identical withthe first named agency means except for a difference in gritcharacteristic, and motorized control means for selectively shifting theabrasive element of one such agency means out of its cutting zone andfor shifting the other element into active face engagement, therespective cutting zones of such abrasively different elements beingdisposed in substantial parallelism with each other.

2. In a grinding machine for treating sheet stock and which machinecomprises a shiftably guided presser agency supplied with abrasive tapepossessing a certain grit characteristic that is operatively interposedbetween tape backing means and a treated sheet side face to establish acutting zone therealong, a companion presser agency substantially likethe first named agency except for a distinctive grit characteristic andwhich abrasively distinctive tapes have their respective cutting zonesdisposed in substantial parallelism .controlled feed means forindependently advancing said tapes toward their respective cuttingzones, and manipulative control means for selectively shifting one suchagency out of its cutting zone and for halting the tape feed meansassociated therewith.

3. In a abrasive machine for treating sheet stock and which machinecomprises dual presser agencies each provided with a plurality ofshiftably mounted shoe components distributed tandemwise athwart atreated sheet side face with the lfl shoes of one such agency keptlaterally spaced in small floor space for its effective output capacity.

The foregoing rather explicit disclosure will it is believed, makeevident to those skilled in this art, the more outstanding commercialadvantages afforded by my improvements over the prior grinder art. Sincecertain aspects of. my controls are likely to find application topurposes other than the treatment of a rotor sheath, I reserve the rightto modify the structural features specifically disclosed in my singleillustrative embodiment adapted for both coarse or fine grinding, allwithout departing from the'spirit and scope of my invention heretoforedescribed and more particularly defined in the appended claims.

I claim:

1. In an abrasive machine for treating elongated sheet stock and whichmachine comprises presser agency means provided with backing a staggeredrelation to those of the other agency and which several shoes areprovided with header means for exerting a substantially equalizedbacking thrust thereon, an abrasive element possessing a certain gritcharacteristic interposed between each such shoe component and said sideface and wh ch elements when actively engaged afford two series ofsubstantially parallel abrasive regions lying in said face to conjointlyestablish a virtually uninterrupted cutting zone, companion dual presseragencies substantially similar to the first named agencies except for adifference in grit characteristic and which companion agencies havetheir conjoint cutting zone disposed in the aforesaid face, and controlmeans retaining the abrasive elements of the first named dual agenciesout of cutting engagement with said face while the elements of thecompanion agencies are actively engaged.

4. In an abrasive machine for treating sheet stock, said machinecomprising driven rotor means adapted to have such stock applied to anddragged by a portion of the rotor perimeter and exposing a rotatingsheet side face for treatment, a presser agency equipped with shiftablyguided backing means that serves an abrasive element interposed betweensaid backing means and the exposed side face to establish a cutting zoneextending crosswise of said face and lying in a curved surface centeredabout the rotor axis, a substantially similar companion presser agencyarranged to co-operate with the aforesaid face to provide for analternative cutting zone lying in substantial parallelism with the firstnamed zone,

and control means for shifting the respective guided backing means inunison to selectively disengage the abrasive element of one such presseragency and bring the element of the other agency into engagement withthe cutting zone thereof.

5. In an abrasive machine for treating sheet stock, said machinecomprising driven rotor means adapted to have such stock applied to anddragged by a portion of the rotor perimeter and expose a curved rotatingsheet side face for treatment, a pair of spaced levers alignedly pivotedto rock in unison and having their respective fulcrums disposed inparallelism with the rotor axis, header beam means spanningcorresponding ends of said levers and which beam means mounts aresiliently backed shoe arranged to co-operate with an abrasive elementfor imposing a regulatable grit thrust thereon, said shoe being guidedby said levers from a certain neutral position into operative gritbacking engagement with said face, and manipulative means forprogressively rocking said levers to impose a gradually increasingthrust upon such engaged shoe.

6. In an abrasive machine for treating sheet stock, said machinecomprising driven rotor means adapted to have such stock applied aboutthe rotor perimeter and expose a rotating sheet side face for treatment,a pair of spaced cantilevers alignedly pivoted to rock in unison andhaving their respective fulcrums disposed in parallelism with the rotoraxis, complementary header beam means respectively spanningcorresponding ends of said cantilevers and which beam means each mountsa resiliently backed shoe arranged to co-operate with an abrasiveelement for imposing a regulatable grit thrust thereon, the shoeassociated with one such beam means being guided by said cantileversfrom a certain neutral position into operative grit backing engagementwith said face, means for progressively rocking said cantilevers toimpose a gradually increasing thrust upon such engaged shoe, andindicator means registering the extent of such thrust.

7. In a grinder machine for abrading sheet stock, said machinecomprising driven rotor means adapted to have such sheet applied to aportion of the rotor perimeter and expose a rotating side face fortreatment, a pair of laterally spaced trunnion shafts mounted to rock inparallelism with the rotor axis and respectively provided with shiftablyguided shoe means controllably arranged to back an associated abrasiveelement and which shoe means are alternatively shiftable toward saidface, and operatively interconnected arm means serving to rock bothtrunnion shafts in unison.

8. In a grinder machine for abrading sheet stock, said machinecomprising driven rotor means adapted to have such sheet applied to aportion of the rotor perimeter and expose a rotating side face thereoffor treatment, mated trunnion shafts respectively mounted in substantialparallelism with the rotor axis, a pair of aligned cantilevers spacedlyinstalled upon each such shaft, complementary header beam meansrespectively spanning corresponding end regions of each pair ofcantilevers and which shiftably guided beam means are each equipped withbacking shoe means that respectively co-operate with an associatedabrasive element, actuated rocker arm means for each such trunnionshaft, and adjustable tie rod means interconnecting the respectiverocker arms and which tie rod means when adjustably altered in lengthbrings one such abrasive element of each mated shaft into operativeengagement with said face.

9. In an abrasive machine for treating sheet stock, said machinecomprising driven rotor means adapted to have such sheet applied to anddragged by a portion of the rotor perimeter and expose a rotating sideface for treatment, a pair of spaced lever means alignedly fulcrumed torock in unison and having their respective fulcrums disposed insubstantial parallelism with the rotor axis, header beam means shiftablyguided by said lever means and which beam means is provided withmultiple transverse apertures respectively arranged to mount a slidablemember of which one end region carries backing shoe means thatco-operates with an associated abrasive element located in adjacency tosaid face, resilient thrust means for each such slide member, said meansbeing arranged to collectively react upon said beam means and impose asubstantially equalized grit backing thrust upon the several shoe meansirrespective of the resulting beam deflection, and controlled rockingmeans for said lever means whereby to selectively shift said beam meansand associated shoe toward or away from said face.

10. In an abrasive machine for treating sheet stock, said machinecomprising laterally spaced housing standards respectively equipped withforwardly disposed bearing means, driven rotor means installed betweensaid bearing means and adapted to have such stock sheathingly servicedabout the rotor perimeter to expose a sheet side face for treatment, aspool shaft spanning a rearward portion of said standards in substantialparallelism with the rotor axis to leave the forward portion of therotor perimeter unobstructed for stock servicing and which spool shaftis arranged to carry a series of tape supply spools thereon, spindlemeans alignedly mounting a corresponding series of reels thereon,shiftably mounted header beam means arranged to carry a correspondingseries of backing shoes that respectively lie adjacent the exposed sheetface, each such tape supply being separately threaded along an advancingtravel path interposed between the corresponding shoe thereof and saidface and whereupon the several tapes are respectively affixed to the hubof a corresponding reel, and controllable drive means rotating theseveral reels in unison.

11. In an abrasive machine for treating sheet stock, said machinecomprising laterally spaced housing standards respectively equipped withbearing means, driven rotormeans installed between said bearing meansand adapted to have such stock sheathingly applied to a portion of therotor perimeter to expose a sheet side face for treatment, complementarycantilever means alignedly fulcrumed to rock in unison, a pair of headerbeam means respectively bridging corresponding end regions of saidcantilever means and shiftably guided thereby, said beam means beingeach provided with a tape backing shoe disposed in adjacency to saidside face, a pair of spool-carrying shafts that span said standards insubstantial parallelism with the rotor axis and respectively provide foran independent supply of roll tape possessing distinctive gritcharacteristics and which abrasively different tapes are separatelyadvanced toward the shoe corresponding to one such shaft, a pair ofindependently actuated spindle means respectively mounting a tape feedreel thereon that serves one kind of such tape, and interlocked controlmeans for selectively shifting one of said shoes toward said face andfor responsively feeding the tape leading thereto.

12. In an abrasive machine for superficially treating a work piece andwhich machine comprises shiftably guided header beam means that carriesa tape backing shoe disposed in adjacency with the treated work piecesurface, a bodily demountable spool carrying a roll of abrasive tapethereon, a tape of! take reel mounted in substantial axial parallelismwith the spool, said tape being advanced along a travel path leading tothe reel and having a medial length region operatively interposedbetween the shoe and said surface, and clutched drive means positivelyrotating said reel in one direction for initially transferring roll tapeonto said reel, said clutched drive means when released allowing thetape to be reversely transferred back to the demountable spool.

13. In an abrasive machine for treating sheet stock, said machinecomprising driven rotor means adapted to have such stock applied to therotor perimeter to expose a rotating sheet side face for treatment,controlled main tractor means for intermittently driving the rotor meansat comparatively high speed, shiftably guided beam means that carries anabrasive element disposed to grind said face and which element isshiftable into a neutral position upon completion of such grinding, andauxiliary speed reducing means provided with a clutchable output shaftthrough which during intermittency of the main tractor means to slowlydrive the rotor.

14. In an abrasive machine comprising driven rotor means whose perimeteris equipped with an immovable gripping edge and a cooperating movablegripping edge respectively disposed in substantial parallelism with therotor axis, said perimeter being adapted to have a sheet of stockapplied thereto in sheathlike fashion to present an exteriorly exposedface for abrasive treatment, the respective sheet ends being radiallyinturned to constitute complementary lips respectively hooked intoengagement with said gripping edges, and automatic compensating meansincluding shiftable mounted keeper bar means of which an edgeconstitutes the aforesaid movable gripping edge, and thrust means urgingsuch bar edge in a direction tangentially of the rotor perimeter andserving to maintain a substantially unslackened tension along theapplied sheet face when subjected to abrasive heating.

15. In an abrasive machine for treating sheet stock, said machinecomprising driven rotor means having a transversely niched perimeter,actuated keeper means shiftably disposed in such rotor niche andequipped with a lip gripping edge, said perimeter being adapted to havea sheet of stock embracingly applied thereto in overlapping relation tothe keeper means and present an exteriorly exposed face for abrasivetreatment, the respective sheet ends being radially inturned toconstitute complementary lips of which one such lip is gripped by therelatively shiftable keeper edge, a mated anchored gripping edge forsaid perimeter serving to fixedly retain the other lip, thrust meansactuating such keeper edge in a direction tangential to the rotorperimeter to impose a corresponding directed txamme tension along theapplied sheet, and a abrasive element placed into operative engagementwith the exposed face of such tensioned rotating sheet.

16. In an abrasive machine comprising driven rotor means provided with atransversely slotted perimeter and which perimeter is adapted to have asheet of stock embracingly applied thereto possessing a coeflicient ofexpansion lower than that of the perimeter, said sheet presenting anexteriorly exposed face for abrasive treatment and the respective endsthereof being radially inturned to constitute complementary lips, keepermeans mounted in the rotor slot and including a swingable toggle edgearranged to grip one of the aforesaid lips and subject the applied sheetto initial tension, a mated grippin edge for the rotor serving to retainthe other lip, and an abrasive element operating on said face and whichsheet upon becoming heated continues by differential expansion to keepsaid lips engaged with their respective gripping edges.

1'7. In an abrasive machine for treating sheet stock, said machinecomprising a jacketed rotor mounted upon a driven axle, the rotor Jacketbeing inducedly cooled by circulated fluid and the rotor perimeter beingprovided with a pair of diametrically opposed slots respectively havingkeeper means installed therein, said perimeter being adapted to have apair of prefabricated semi-cylindrical sheet components sheathinglyapplied thereto to segmentally complete a virtually endless rotatingface that circumscribes said axle, the respective ends of each suchprefabricated sheet component being radially inturned to constitutecomplementary lips that are respectively hooked into said opposed slots,keeper means overlapped by one such sheet component and serving toretain a lip thereof, and an abrasive element placed into operativeengagement with said rotating face.

18. In an abrading machine for treating sheet stock, said machinecomprising driven rotor means adapted to have such stock applied to therotor perimeter to prepare an exposed sheet side face for treatment,shiftably guided header beam means provided with backing shoe meansarranged to be shifted toward or away from said face, a guide rollercarried along each side of said beam means in registry with the shoemeans, and a supply of abrasive tape of which a length region isalignedly threaded over both such rollers and interposed between theshoe means and said face.

19. In a grinder machine for superficially treating sheet stock, saidmachine comprising impelled rotor means adapted to have such stockapplied to a portion of said means and expose a sheet side face fortreatment, shiftably guided header means provided with a slidable memberof which one end region carries a backing shoe and which shoe isarranged to be bodily moved toward or away from said face in unison witha shift of the header means, resilient means thrusting against saidheader means and serving to urge the backing shoe toward the treatedface, an abrasive element interposed between said shoe and face, andstop means limiting the shoe travel toward said face.

LOUIS ILLMER.

